Diogo Jota rounded off the scoring late on, slotting home after being put through on goal.

The result took some of the shine off Leicester's previous performances in the Champions League this season, but they can now look forward to the draw for the last 16, which takes place on Monday at around 11:00 GMT.

Pressure off? Not quite

Leicester (right heat map) barely touched the ball in the Porto box and did not force goalkeeper Iker Casillas into a single save all night

Passage to the knockout stage might have been secured before Wednesday's game but Ranieri will still have felt the need for a good performance and result.

While they have exceeded expectations in the Champions League, the Foxes' Premier League title defence has been disappointing and they sit just two points above the relegation zone.

Jamie Vardy and Riyad Mahrez have so far been unable to recapture their form of last season and were two of the frontline players not to travel to Portugal. Instead, it was left to Leicester's bit-part players to put on a show.

That, unfortunately, did not happen.

The Foxes had let in just one goal in their five previous Champions League games but looked capable of conceding from every Porto attack. Their defence was disjointed, with Silva allowed to rise too easily for the hosts' first while Corona was left unmarked for the second.

In attack, Shinji Okazaki and Ahmed Musa offered little, with the latter replaced by Leonardo Ulloa at half-time. The change did nothing to improve Leicester's attacking threat as they finished the game without a shot on target, although Ulloa did hit the crossbar late on.

Ranieri would have liked to have seen his fringe players stake a claim for a regular place in his starting XI, but instead their performance may have left the Italian concerned about his side's strength in depth.

Who could Leicester face in the last 16? One of:

Paris St-Germain

Benfica

Bayern Munich

Bayer Leverkusen

Real Madrid

Sevilla

Tinkerman tinkering too much?

Claudio Ranieri said earlier this week that he did not feel under pressure, despite recent results

Ranieri made sweeping changes for this game to give his key players a rest, but the Italian does appear to be struggling to find his strongest XI.

The Italian has not named an unchanged side for two consecutive games since 10 September - 14 games ago.

It may be that a lack of consistency is affecting the Leicester players but Ranieri will be forced to rethink his starting line-up once again for this weekend's game against Manchester City.

Drinkwater - a crucial player for Leicester in their title-winning season - was substituted with a knee injury towards the end of the second half and an extended absence would be a blow for the Foxes, although Ranieri said after the game that he did not believe the injury to be serious.

Danny Drinkwater, centre, is now level with Diego Maradona for European Cup/CL appearances with six

Dates for the diary

Last 16, first leg:

14-15 February and 21-22 February

Last 16, second leg:

7-8 March and 14-15 March

'We didn't show our character'

"I have a clearer idea about my players now," said Ranieri afterwards.

"We wanted to see something different, but it was too easy for Porto. We didn't make them fight to score.

"We can lose, but I want us to show our character and our strength. We didn't do that well enough."

What next?

Leicester return to Premier League action this weekend as they look to start their climb up the table. They host Manchester City on Saturday before travelling to Bournemouth on Tuesday, 13 December.

An unwanted place in history - the stats

This was the heaviest defeat by an English side in Europe since Everton's 5-0 defeat at Benfica in the 2009-10 Europa League.

Ben Hamer is the first English goalkeeper to concede five goals on his Champions League debut. Gary Walsh and Nigel Martyn both conceded four on their CL debuts.

FC Porto have lost just three of their past 22 Champions League home games (W14 D5 L3).

This was the second match this season in which Leicester have conceded 3+ goals in the first half (the other was v Man Utd in the Premier League). They didn't do this at all in 2015-16.

Andre Silva scored in three of FC Porto's final four Champions League group stage matches this season (four goals).

Ben Chilwell became only the third English teenager to start a Champions League game this season, after Tosin Adarabioyo and Patrick Roberts.